You know what they say -- your first 500,000 sales are easy, it's the next 500,000 that takes work! OK, no one has ever said that. Sure, diminishing returns are a thing, but I doubt Campo Santo is particularly upset that it's sold over one million copies of Firewatch, hitting the milestone "sometime late last year".
It's interesting when you consider the developer hit half-a-million a month after release, which means it took another nine months to double that number.
Sometime late last year we sold our one millionth copy of Firewatch. Thank you all so much! pic.twitter.com/7LSTqWuU8Q
— Campo Santo (@camposanto) January 3, 2017
I'm not sure on the maths, but does that mean it'll take almost seven years (nine squared) to get to two million?